Lithium titanium oxide, method of preparing lithium titanium oxide, and lithium rechargeable battery including lithium titanium oxide

ABSTRACT

A spherical primary particle of a lithium titanium oxide of which average diameter is in the range of about 1 to about 20 μm, a method of preparing the spherical primary particle of the lithium titanium oxide, and a lithium rechargeable battery including the spherical primary particle of the lithium titanium oxide.

CLAIM OF PRIORITY

This application claims the benefit of Korean Patent Application No.10-2009-0096819, filed on Oct. 12, 2009, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

One or more embodiments of the present invention relate to a lithiumtitanium oxide, a method of preparing the lithium titanium oxide, and alithium rechargeable battery including the lithium titanium oxide.

2. Description of the Related Art

A lithium ion battery is a kind of a rechargeable battery that generateselectricity by motion of lithium ions between a cathode and an anode.The lithium ion rechargeable battery generally includes a cathode, ananode, an electrolyte, and a separator. Cathode and anode activematerials as components of the lithium ion battery constitute astructure in which lithium ions move by reversible reactions from theanode active material to the cathode active material during dischargingand vice versa during charging.

A lithium metal has been used as an anode active material. However, whena lithium metal is used in a battery, short circuits may occur in thebattery due to the formation of dendrite, and thus the battery mayexplode. Thus, a carbon-based material instead of a lithium metal hasbeen widely used as an anode active material.

Examples of the carbon-based active material may include crystallinecarbon such as graphite and artificial graphite, and amorphous carbonsuch as soft carbon and hard carbon. However, although the amorphouscarbon has a large capacity, the amorphous carbon has highirreversibility during charging and discharging. Graphite isrepresentatively used as crystalline carbon. In addition, graphite has ahigh theoretical restrictive capacity of 372 mA h/g, and thus graphiteis used as an anode active material. However, although graphite or acarbon-based active material have a relatively high theoreticalcapacity, the theoretical capacity is no more than about 380 mAh/g, andthus they may not be used to develop a high-capacity lithium battery.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention include a sphericalprimary particle of a lithium titanium oxide having a spherical shape.

One or more embodiments of the present invention include a method ofpreparing the spherical primary particle of the lithium titanium oxide.

One or more embodiments of the present invention include a lithiumrechargeable battery including the spherical primary particle of thelithium titanium oxide.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to one or more embodiments of the present invention, aspherical primary particle of a lithium titanium oxide is provided,wherein an average diameter of the spherical primary particle is about 1to about 20 μm.

An average diameter of the spherical primary may be about 2.5 μm toabout 4.5 μm.

A spherical degree of the spherical primary particle may be in the rangeof about 0.90 to about 0.95, and the spherical degree may be given byEquation 1:

Equation 1

Spherical Degree=short-axis length of the particle/long-axis length ofthe particle.

The spherical primary particle of the lithium titanium oxide may includea spinel structure.

The spherical primary particle of the lithium titanium oxide may includelithium titanate (Li₄Ti₅O₁₂).

The specific primary particle may have a specific surface area of about2.8 m²/g to about 6.0 m²/g, and a tap density of about 0.8 g/cc to 2.0g/cc.

The specific primary particle may have an average diameter of about 2.5μm to about 4.5 μm, a specific surface area of about 4.8 m²/g to about5.7 m²/g, and a tap density of about 1.1 g/cc to about 1.8 g/cc.

The spherical primary particle of the lithium titanium oxide may be usedfor an anode active material for a lithium rechargeable battery.

According to one or more embodiments of the present invention, a lithiumrechargeable battery includes the spherical primary particle of thelithium titanium oxide.

According to one or more embodiments of the present invention, a methodof preparing a spherical primary particle of a lithium oxide includesmixing a lithium salt and titania to prepare a mixture; performingheat-treatment on the mixture at a temperature of about 700 to about900° C.; and atomizing a resultant on which the heat-treatment isperformed.

The lithium salt may be at least one selected from the group consistingof lithium nitrate, lithium hydroxide, lithium chloride, lithium oxideand lithium carbonate.

The titania may be rutaile-phase titania.

The tiania may have a spherical shape having a diameter of about 200 nmto about 800 nm.

The tiania may have a monodisperse shape.

A mean diameter (D50) of the titania may be about 0.45 μm to about 0.55μm, and a mean diameter (D90) of the titania is about 0.76 μm to about0.80 μm.

A spherical degree of the spherical primary particle may be in the rangeof about 0.90 to about 0.99, and the spherical degree may be given byEquation 1:

Equation 1

Spherical Degree=short-axis length of particle/long-axis length ofparticle.

The heat-treatment may be performed at a temperature of about 800 toabout 900° C.

The heat-treatment may be performed for about 0.5 to about 4 hours.

The spherical primary particle of the lithium titanium oxide may be usedfor an anode active material for a lithium rechargeable battery.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings of which:

FIG. 1 is a scanning electron microscope (SEM) image of a lithiumtitanium oxide prepared in Comparative Example 1;

FIG. 2 is a graph showing X-ray diffraction (XRD) of a lithium titaniumoxide according to an embodiment of the present invention;

FIGS. 3A and 3B are scanning electron microscope (SEM) images of alithium titanium oxide according to an embodiment of the presentinvention; and

FIG. 4 is a graph showing an analysis result of a particle sizedistribution of a lithium titanium oxide according to an embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to embodiments.

In order to develop a lithium ion rechargeable battery having goodperformances such as rapid charging/discharging and long lifetime,active research has been recently conducted on using lithium titanate(Li₄Ti₅O₁₂), which is a metal oxide having a spinel structure, as ananode active material.

Li₄Ti₅O₁₂ does not generate a solid state interphase (SEI) that isgenerated in an accompanying reaction between a graphite-based anodeactive material and an electrolyte. Thus, Li₄Ti₅O₁₂ is much better thangraphite in terms of the irreversible capacity, and has excellentreversibility for lithium ions to be inserted into and released fromLi₄Ti₅O₁₂ in a repetitive charging/discharging cycle. In addition,Li₄Ti₅O₁₂ is very stable in terms of its structure, and thus Li₄Ti₅O₁₂may lead to improved performances of a rechargeable battery, such aslong lifetime.

A method of preparing Li₄Ti₅O₁₂ may be largely classified into a liquidphase method and a solid phase method.

The liquid phase method is used to prepare a precursor having a newshape, and may be used to obtain powders having a fine particle size anda high chemical uniformity by reducing a distance between ions so as tolower a reaction temperature and to reduce a reaction time. However,materials used in the liquid phase method are expensive. In addition,negative ion impurities are also precipitated to be mixed with particlesby lattice bonding and to be absorbed into surfaces of the powders,which is a serious problem.

On the other hand, the solid phase method is very simple. The costs ofthe solid phase method are much lower and reproducibility is higher,compared to the liquid phase method. However, impurities may be mixedduring pulverization, and it is difficult to change a shape of a powderinto a spherical shape by using a general method.

A shape of an active material used to form a battery is very important.An active material having a spherical shape is advantageous for easilypreparing an electrode and for increasing a packing intensity, and thusthe active material may increase the amount of a battery including theactive material. Accordingly, a technology of preparing an activematerial in a spherical shape is necessary to obtain a lithium ionrechargeable battery that is highly stable and is rapidly charged anddischarged.

According to an embodiment of the present invention, a spherical primaryparticle of a lithium titanium oxide has an average diameter of about 1to about 20 μm. For example, an average diameter of the sphericalprimary may be about 2.5 μm to about 4.5 μm.

According to an embodiment of the present invention, a sphericalparticle of lithium titanium oxide may have a spherical degree in therange of about 0.90 to about 0.95.

The spherical degree is given by Equation 1:

Equation 1

Spherical Degree=short-axis length of the particle/long-axis length ofthe particle.

According to Equation 1, a perfect sphere has a spherical degree of 1.In addition, as the spherical degree of a particle is closer to 1, theparticle has a shape closer to a perfect sphere.

According to an embodiment of the present invention, a spherical primaryparticle of a lithium titanium oxide may have a spinel structure, andthe spherical primary particle of the lithium titanium oxide may includeLi₄Ti₅O₁₂.

According to an embodiment of the present invention, the specificprimary particle may have an average diameter of about 1 μm to about 20μm, a specific surface area of about 2.8 m²/g to about 6.0 m²/g, and atap density of about 0.8 g/cc to 2.0 g/cc.

According to an embodiment of the present invention, the specificprimary particle may have an average diameter of about 2.5 μm to about4.5 μm, a specific surface area of about 4.8 m²/g to about 5.7 m²/g, anda tap density of about 1.1 g/cc to about 1.8 g/cc.

According to an embodiment of the present invention, the sphericalprimary particle of the lithium titanium oxide may be used for a cathodeor anode active material for a lithium rechargeable battery, forexample, may be used for an anode active material for a lithiumrechargeable battery.

Since the spherical primary particle of the lithium titanium oxide maybe formed of titania having a monodisperse shape, which will bedescribed later, the spherical primary particle of the lithium titaniumoxide has the specific surface and the tap density having theabove-described ranges.

Next, a method of preparing a spherical primary particle of a lithiumtitanium oxide will be described.

According to an embodiment of the present invention, a method ofpreparing a spherical primary particle of lithium titanium oxideincludes mixing a lithium salt and titania; performing heat-treatment onthe mixture at a temperature of about 700 to about 900° C.; andatomizing the resultant on which the heat-treatment is performed.

The atomizing may be pulverization, disintegration, or the like. Forexample, the atomizing may be disintegration.

According to an embodiment of the present invention, the lithium saltmay be at least one selected from the group consisting of lithiumnitrate, lithium hydroxide, lithium chloride, lithium oxide and lithiumcarbonate.

According to an embodiment of the present invention, titania may have aspherical shape, and may be a monodisperse spherical fine-particlehaving an average diameter of several nonometers and a small diameterdispersity, which is used as a precursor of Li₄Ti₅O₁₂. The averagediameter of the titania may be in the range of about 10 to about 1,000nm. However, when the titania has a diameter of several tens ofnanometers, titania particles may be aggregated to each other during theheat-treatment. Thus, titania having an average diameter of about 200 nmto about 800 nm may be used. The titania may be anatase-phase titania.However, in order to maintain a spherical shape of the titania and toresolve the problem of aggregation between particles, the titania may berutile-phase titania that is stable at a high temperature.

According to an embodiment of the present invention, the titania mayhave a monodisperse shape, and may have a spherical degree in the rangeof about 0.90 to about 0.99.

A spherical degree is given by Equation 1.

Equation 1

Spherical Degree=short-axis length of particle/long-axis length ofparticle.

A degree of monodispersion of titania may be determined based on a meandiameter (D50) and a mean diameter (D90). A D50 of the titania may beabout 0.45 μm to about 0.55 μm, and a D90 of the titania may be about0.76 μm to about 0.80 μm.

The terminologies ‘D50’ and ‘D90’ are well known to one of ordinaryskill in the art. In short, the D50 denotes an intermediate diameter ofa particle, and the D90 denotes a maximum diameter of a particle. Thedetailed description will be easily understood with reference to recitedreferences.

As described above, when the titania having the monodisperse shape withthe above-mentioned ranges is used, the spherical primary particle ofthe lithium titanium oxide has the average diameter with theabove-mentioned ranges.

In the mixing of the lithium salt and the titania, material powders areput in Li:Ti=4:5, a ball milling operation is performed on the lithiumand the titania, and then the lithium salt and the titania are regularlymixed.

During the heat-treatment, the heat-treatment may be performed for about0.5 to about 4 hours at a temperature of about 800 to about 900° C.

When rutile-phase titania is used, if the heat-treatment is performed ata temperature higher than 900° C., another material instead of Li₄Ti₅O₁₂may be generated.

During the heat-treatment, lithium is made to a solid solution at atemperature equal to or greater than a melting point, and Li₄Ti₅O₁₂having a spinel structure is crystallized. A period to make lithiumchange into a solid solution, which is one of conditions of theheat-treatment, may be determined according to a lithium salt, and maybe in the range of about 0.5 to about 1.5 hours at a temperature arounda melting point of a lithium salt. When the period to make lithiumchange into a solid solution is longer than 1.5 hours, particles arelargely grown to form a coarse particle, and an aggregation statebetween particles is getting more serious in proportion to a period oftime. A crystallization temperature may be in the range of about 700 toabout 900° C., for example, about 800 to about 900° C. Within theseranges, the crystalline degree and yield of Li₄Ti₅O₁₂ may be optimized.

In a last operation, the preparation of Li₄Ti₅O₁₂ powders is completedby disintegrating Li₄Ti₅O₁₂ powders so as to change them into fineparticles.

According to an embodiment of the present invention, the sphericalprimary particle of the lithium titanium oxide may be used for a cathodeor anode active material for a lithium rechargeable battery, forexample, may be used for an anode active material for a lithiumrechargeable battery.

The spherical degree of a prepared Li₄Ti₅O₁₂ particle may be comparedwith the spherical degree calculated by Equation 1.

The spherical degree of the prepared Li₄Ti₅O₁₂ particle prepared by themethod in which titania having a monodisperse spherical shape is used asa precursor may be adjusted in the range of about 0.90 to about 0.95.

Hereinafter, one or more embodiments of the present invention will bedescribed in detail with reference to the following examples. However,these examples are not intended to limit the purpose and scope of theone or more embodiments of the present invention.

Example 1

Mixed powders were prepared by measuring 16.1 wt % of lithium carbonateand 43.5 wt % of rutile-phase titania of which particle had a sphericaldegree of 0.94 (D50=0.49 μm and D90=0.78 μm), putting the mixture in acontainer formed of zirconia and filled with zirconia balls, performinga milling operation at a rotation speed of 450 rpm for 6 hours, and thendisintegrating and mixing raw materials.

A final resultant was obtained by sintering the mixed powders in anoxygen atmosphere and a temperature environment where a temperatureincreased by 5° C. every minutes, at a temperature of 685° C. for 1.5hours, and at a temperature of 800° C. for 5 hours, and thendisintegrating the sintered material in a disintegrator.

FIG. 2 is a graph showing X-ray diffraction (XRD) of a lithium titaniumoxide according to an embodiment of the present invention. Referring toFIG. 2, according to analysis of X-ray crystalline structure, Li₄Ti₅O₁₂having a spinel structure was successfully synthesized

FIG. 4 is a graph showing an analysis result of a particle sizedistribution of a lithium titanium oxide according to an embodiment ofthe present invention. Referring to FIG. 4, it may be seen that thelithium titanium oxide exhibits a monodisperse distribution.

An average spherical degree (Ψ) of the prepared Li₄Ti₅O₁₂ particle wasequal to or greater than 0.92, and an average diameter of the preparedLi₄Ti₅O₁₂ particle was 4.5 μm. In addition, a specific surface area ofthe prepared Li₄Ti₅O₁₂ particle was about 4.8, and a tap density of theprepared Li₄Ti₅O₁₂ particle was 1.1. FIGS. 3A and 3B are scanningelectron microscope (SEM) images of a lithium titanium oxide accordingto an embodiment of the present invention.

Example 2

Mixed powders were prepared by measuring 16.1 wt % of lithium carbonateand 43.5 wt % of anatase-phase titania of which particle had a sphericaldegree of 0.93 (D50=0.51 μm and D90=0.80 μm), putting the mixture in acontainer formed of zirconia and filled with zirconia balls, performinga milling operation at a rotation speed of 450 rpm for 6 hours, and thendisintegrating and mixing raw materials.

Li₄Ti₅O₁₂ powders having a spinel structure was prepared by performingheat-treatment on the mixed powders in an oxygen atmosphere and atemperature environment where a temperature increased by 5° C. everyminutes, at a temperature of 685° C. for 1.5 hours, and a temperature of800° C. for 5 hours, and then disintegrating the sintered material in adisintegrator.

An average spherical degree (Ψ) of the prepared Li₄Ti₅O₁₂ particle wasequal to or greater than 0.91, and an average diameter of the preparedLi₄Ti₅O₁₂ particle was 3.4 μm. In addition, a specific surface area ofthe prepared Li₄Ti₅O₁₂ particle was about 5.3, and a tap density of theprepared Li₄Ti₅O₁₂ particle was 1.5.

Example 3

Mixed powders were prepared by measuring 18.3 wt % of lithium hydroxideand 43.5 wt % of rutile-phase titania of which particle had a sphericaldegree of 0.94 (D50=0.45 μm and D90=0.78 μm), putting the mixture in acontainer formed of zirconia and filled with zirconia balls, performinga milling operation at a rotation speed of 450 rpm for 6 hours, and thendisintegrating and mixing raw materials.

Li₄Ti₅O₁₂ powders having a spinel structure was prepared by sinteringthe mixed powders in an oxygen atmosphere and a temperature environmentwhere a temperature increased by 5° C. every minutes, at a temperatureof 450° C. for 1.5 hours, at a temperature of 800° C. for 5 hours, andthen disintegrating the sintered material in a disintegrator.

An average spherical degree (Ψ) of the prepared Li₄Ti₅O₁₂ particle wasequal to or greater than 0.92, and an average diameter of the preparedLi₄Ti₅O₁₂ particle was 2.5 μm. In addition, a specific surface area ofthe prepared Li₄Ti₅O₁₂ particle was about 5.7, and a tap to density ofthe prepared Li₄Ti₅O₁₂ particle was 1.8.

Comparative Example 1

Mixed powders were prepared by measuring 16.1 wt % of lithium carbonateand 43.5 wt % of amorphous rutile-phase titania, putting the mixture ina container formed of zirconia and filled with zirconia balls,performing a milling operation at a rotation speed of 450 rpm for 6hours, and then disintegrating and mixing raw materials.

A final resultant was obtained by sintering the mixed powders in anoxygen atmosphere and a temperature environment where a temperatureincreased by 5° C. every minute, at a temperature of 685° C. for 1.5hours, and at a temperature of 800° C. for 5 hours, and thendisintegrating the sintered material in a disintegrator.

An average spherical degree (Ψ) of the prepared Li₄Ti₅O₁₂ particle wasequal to or greater than 0.44, and an average diameter of the preparedLi₄Ti₅O₁₂ particle was 1.7 μm. In addition, a specific surface area ofthe prepared Li₄Ti₅O₁₂ particle was about 6.2, and a tap density of theprepared Li₄Ti₅O₁₂ particle was 0.8.

Comparison of Spherical Degree of Li₄Ti₅O₁₂

The spherical degrees measured in Examples 1, 2 and 3 and ComparativeExample 1 are shown in Table 1.

TABLE 1 Average spherical degree (Ψ) Comparative 0.44 Example 1 Example1 0.92 Example 2 0.91 Example 3 0.92

As shown in Table 1, it may be seen that the spherical degree of theLi₄Ti₅O₁₂ particle prepared in Comparative Example 1 is much smallerthan that of the Li₄Ti₅O₁₂ particle prepared in Examples 1, 2 and 3.

FIGS. 1, 3A and 3B are SEM images of Li₄Ti₅O₁₂ particles prepared inComparative Example 1 and Example 1, respectively.

Referring to FIGS. 1, 3A and 3B, the Li₄Ti₅O₁₂ particle of Example 1 hasa almost perfect sphere, but the Li₄Ti₅O₁₂ particle of ComparativeExample 2 has a non-sphere shape, which corresponds to the comparison ofspherical degree with reference to Table 1.

Preparation of Electrode

Example 4

An electrode was prepared by mixing 0.045 g of a material prepared inExample 1 and 0.045 g of graphite (SFG6, available from TimCal) in 0.2 gof a solution of polyvinylidene fluoride (PVDF) (KF1100, available fromGureha Chemistry of Japan) as a binder and 5 wt % of N-methylpyrrolidone(NMP), and then coating the mixture on a copper foil.

Comparative Example 2

An electrode was prepared in the same manner as in Example 4 except that0.045 g of a material prepared in Comparative Example 1 and 0.045 g ofgraphite (SFG6, available from TimCal) were mixed.

Experimental Example 1 Cycle Properties Test

A coin cell of 2016—form was prepared by using the electrodes preparedin Example 4 and Comparative Example 2 as an anode, and a LI metal as acathode, and the coin cell was charged and discharged at a voltagebetween about 1.5 and about 0 V.

A mixed solution of ethylene carbonate (EC), diethylene carbonate (DEC)and fluoro ethylene carbonate (volume ratio: 2/6/2), in which 1.3 M ofLiPF₆ was dissolved, was used as an electrolyte. Charging was performedon a Li electrode up to 0.001 V by supplying a static current of 100 mAper 1 g of an active material, and then static-voltage charging wasperformed while a voltage of 0.001 V was maintained until a measuredcurrent reached 10 mA per 1 g of the active material. After a pauseperiod of the coin cell on which charging was completed for about 10minutes, static-current discharging was performed up to a voltage of 1.5V by supplying a static current of 100 mA per 1 g of the activematerial. The result is shown in Table 2.

TABLE 2 Initial Discharging Initial Effi- Capacity Maintenance Capacity(mAh/g) ciency (%) (%) @ 50 cycles Example 4 167 99.6 99.3 Comparative164 98.7 97.8 Example 2

As shown in Table 2, it may bee seen that the initial capacity andinitial efficiency of Example 4 are larger than in Comparative Example2.

As described above, according to the one or more of the aboveembodiments of the present invention, by a method of preparing aspherical primary particle of a lithium titanium oxide, a sphericalprimary particle of a lithium titanium oxide having a higher sphericaldegree may be prepared at a lower preparing cost, compared to a generalmethod.

According to the one or more of the above embodiments of the presentinvention, a spherical primary particle of a lithium titanium oxide maybe adjusted in a spherical shape, thereby increasing the tab density andpacking density of an active material.

According to the one or more of the above embodiments of the presentinvention, a spherical primary particle of a lithium titanium oxide mayhave a spherical shape, and thus a packing operation is easilyperformed, and the amount of a lithium rechargeable battery includingthe lithium titanium oxide may increase.

It should be understood that the exemplary embodiments described thereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

1. A spherical primary particle of a lithium titanium oxide, wherein an average diameter of the spherical primary particle is about 1 to about 20 μm.
 2. The spherical primary particle of the lithium titanium oxide of claim 1, wherein an average diameter of the spherical primary is about 2.5 μm to about 4.5 μm.
 3. The spherical primary particle of the lithium titanium oxide of claim 1, wherein a spherical degree of the spherical primary particle is in the range of about 0.90 to about 0.95, and wherein the spherical degree is given by Equation 1: Equation 1 Spherical Degree=short-axis length of the particle/long-axis length of the particle.
 4. The spherical primary particle of the lithium titanium oxide of claim 1, wherein the spherical primary particle of the lithium titanium oxide comprises a spinel structure.
 5. The spherical primary particle of the lithium titanium oxide of claim 1, wherein the spherical primary particle of the lithium titanium oxide comprises lithium titanate (Li₄Ti₅O₁₂).
 6. The spherical primary particle of the lithium titanium oxide of claim 1, wherein the specific primary particle has a specific surface area of about 2.8 m²/g to about 6.0 m²/g, and a tap density of about 0.8 g/cc to 2.0 g/cc.
 7. The spherical primary particle of the lithium titanium oxide of claim 1, wherein the specific primary particle has an average diameter of about 2.5 μm to about 4.5 μm, a specific surface area of about 4.8 m²/g to about 5.7 m²/g, and a tap density of about 1.1 g/cc to about 1.8 g/cc.
 8. The spherical primary particle of the lithium titanium oxide of claim 1, wherein the spherical primary particle of the lithium titanium oxide is used for an anode active material for a lithium rechargeable battery.
 9. A lithium rechargeable battery comprising the spherical primary particle of the lithium titanium oxide of any one of claims 1 through
 8. 10. A method of preparing a spherical primary particle of a lithium oxide, the method comprising: mixing a lithium salt and titania to prepare a mixture; performing heat-treatment on the mixture at a temperature of about 700 to about 900° C.; and atomizing a resultant on which the heat-treatment is performed.
 11. The method of claim 10, wherein the lithium salt is at least one selected from the group consisting of lithium nitrate, lithium hydroxide, lithium chloride, lithium oxide and lithium carbonate.
 12. The method of claim 10, wherein the titania is rutaile-phase titania.
 13. The method of claim 10, wherein the tiania has a spherical shape having a diameter of about 200 nm to about 800 nm.
 14. The method of claim 10, wherein the tiania has a monodisperse shape.
 15. The method of claim 14, wherein a mean diameter (D50) of the titania is about 0.45 μm to about 0.55 μm, and wherein a mean diameter (D90) of the titania is about 0.76 μm to about 0.80 μm.
 16. The method of claim 10, wherein a spherical degree of the spherical primary particle is in the range of about 0.90 to about 0.99, and wherein the spherical degree is given by Equation 1: Equation 1 Spherical Degree=short-axis length of particle/long-axis length of particle.
 17. The method of claim 10, wherein the heat-treatment is performed at a temperature of about 800 to about 900° C.
 18. The method of claim 10, wherein the heat-treatment is performed for about 0.5 to about 4 hours.
 19. The method of claim 10, wherein the spherical primary particle of the lithium titanium oxide is used for an anode active material for a lithium rechargeable battery. 